Cubic Cu2O nanoparticles decorated on TiO2 nanofiber heterostructure as an excellent synergistic photocatalyst for H2 production and sulfamethoxazole degradation

We report a simple strategy for providing a homogenous TiO2 nanofibre host environment to stabilize Cu2O nanoparticles with an average size of ∼60 nm and high dispersibility. We found that the small fraction of Cu2O nanoparticles in direct contact/partially submerged with TiO2 nanofibre arrays (diameter ∼300 nm and length ∼650 nm) showed excellent synergistic photocatalytic performance for an H2 production rate of 48 μmol g-1  h-1 with an apparent quantum efficiency of 3.6 %. The H2 production rate was much higher (factor of ∼6.5 times) compared with unmodified TiO2-NF. In addition, the synergistic Cu2O/TiO2-NF photocatalyst showed significant oxidative-degradation of sulfamethoxazole (7 × 10-2 mmol g-1  min-1) and was highly stable during five cycles. The small fraction of Cu2O nanoparticles are well dispersed and form heterojunction interfaces to promote charge transfer and provide active sites. This argument is verified by morphology characterisation, band alignment, energy-resolved distribution of electron traps, electrochemical transient photocurrent, and electrochemical impedance (EIS). In addition, a detailed discussion is provided regarding the surface and bulk elemental composition determined by X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), and X-ray absorption near edge structure (XANES).